[Leg-raised sit-ups] mainly exercises abdominal muscles.

Lie on your back with your lower legs resting on the chair, with the upper and lower legs forming an angle of approximately 90 degrees.

Cross your hands behind your head. Use the strength of your abdominal muscles to roll up your upper body toward your thighs, and then slowly return to the starting position without stopping during the entire process.

Exercise 4 groups of 20 times every other day.